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linux-sg2042/drivers/iio/chemical/ccs811.c

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/*
* ccs811.c - Support for AMS CCS811 VOC Sensor
*
* Copyright (C) 2017 Narcisa Vasile <narcisaanamaria12@gmail.com>
*
* Datasheet: ams.com/content/download/951091/2269479/CCS811_DS000459_3-00.pdf
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* IIO driver for AMS CCS811 (I2C address 0x5A/0x5B set by ADDR Low/High)
*
* TODO:
* 1. Make the drive mode selectable form userspace
* 2. Add support for interrupts
* 3. Adjust time to wait for data to be ready based on selected operation mode
* 4. Read error register and put the information in logs
*/
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/module.h>
#define CCS811_STATUS 0x00
#define CCS811_MEAS_MODE 0x01
#define CCS811_ALG_RESULT_DATA 0x02
#define CCS811_RAW_DATA 0x03
#define CCS811_HW_ID 0x20
#define CCS811_HW_ID_VALUE 0x81
#define CCS811_HW_VERSION 0x21
#define CCS811_HW_VERSION_VALUE 0x10
#define CCS811_HW_VERSION_MASK 0xF0
#define CCS811_ERR 0xE0
/* Used to transition from boot to application mode */
#define CCS811_APP_START 0xF4
/* Status register flags */
#define CCS811_STATUS_ERROR BIT(0)
#define CCS811_STATUS_DATA_READY BIT(3)
#define CCS811_STATUS_APP_VALID_MASK BIT(4)
#define CCS811_STATUS_APP_VALID_LOADED BIT(4)
/*
* Value of FW_MODE bit of STATUS register describes the sensor's state:
* 0: Firmware is in boot mode, this allows new firmware to be loaded
* 1: Firmware is in application mode. CCS811 is ready to take ADC measurements
*/
#define CCS811_STATUS_FW_MODE_MASK BIT(7)
#define CCS811_STATUS_FW_MODE_APPLICATION BIT(7)
/* Measurement modes */
#define CCS811_MODE_IDLE 0x00
#define CCS811_MODE_IAQ_1SEC 0x10
#define CCS811_MODE_IAQ_10SEC 0x20
#define CCS811_MODE_IAQ_60SEC 0x30
#define CCS811_MODE_RAW_DATA 0x40
#define CCS811_MEAS_MODE_INTERRUPT BIT(3)
#define CCS811_VOLTAGE_MASK 0x3FF
struct ccs811_reading {
__be16 co2;
__be16 voc;
u8 status;
u8 error;
__be16 raw_data;
} __attribute__((__packed__));
struct ccs811_data {
struct i2c_client *client;
struct mutex lock; /* Protect readings */
struct ccs811_reading buffer;
struct iio_trigger *drdy_trig;
bool drdy_trig_on;
};
static const struct iio_chan_spec ccs811_channels[] = {
{
.type = IIO_CURRENT,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = -1,
}, {
.type = IIO_VOLTAGE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = -1,
}, {
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_CO2,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 0,
.scan_type = {
.sign = 'u',
.realbits = 16,
.storagebits = 16,
.endianness = IIO_BE,
},
}, {
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_VOC,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 1,
.scan_type = {
.sign = 'u',
.realbits = 16,
.storagebits = 16,
.endianness = IIO_BE,
},
},
IIO_CHAN_SOFT_TIMESTAMP(2),
};
/*
* The CCS811 powers-up in boot mode. A setup write to CCS811_APP_START will
* transition the sensor to application mode.
*/
static int ccs811_start_sensor_application(struct i2c_client *client)
{
int ret;
ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
if (ret < 0)
return ret;
if ((ret & CCS811_STATUS_FW_MODE_APPLICATION))
return 0;
if ((ret & CCS811_STATUS_APP_VALID_MASK) !=
CCS811_STATUS_APP_VALID_LOADED)
return -EIO;
ret = i2c_smbus_write_byte(client, CCS811_APP_START);
if (ret < 0)
return ret;
ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
if (ret < 0)
return ret;
if ((ret & CCS811_STATUS_FW_MODE_MASK) !=
CCS811_STATUS_FW_MODE_APPLICATION) {
dev_err(&client->dev, "Application failed to start. Sensor is still in boot mode.\n");
return -EIO;
}
return 0;
}
static int ccs811_setup(struct i2c_client *client)
{
int ret;
ret = ccs811_start_sensor_application(client);
if (ret < 0)
return ret;
return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
CCS811_MODE_IAQ_1SEC);
}
static int ccs811_get_measurement(struct ccs811_data *data)
{
int ret, tries = 11;
/* Maximum waiting time: 1s, as measurements are made every second */
while (tries-- > 0) {
ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS);
if (ret < 0)
return ret;
if ((ret & CCS811_STATUS_DATA_READY) || tries == 0)
break;
msleep(100);
}
if (!(ret & CCS811_STATUS_DATA_READY))
return -EIO;
return i2c_smbus_read_i2c_block_data(data->client,
CCS811_ALG_RESULT_DATA, 8,
(char *)&data->buffer);
}
static int ccs811_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct ccs811_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
mutex_lock(&data->lock);
ret = ccs811_get_measurement(data);
if (ret < 0) {
mutex_unlock(&data->lock);
iio_device_release_direct_mode(indio_dev);
return ret;
}
switch (chan->type) {
case IIO_VOLTAGE:
*val = be16_to_cpu(data->buffer.raw_data) &
CCS811_VOLTAGE_MASK;
ret = IIO_VAL_INT;
break;
case IIO_CURRENT:
*val = be16_to_cpu(data->buffer.raw_data) >> 10;
ret = IIO_VAL_INT;
break;
case IIO_CONCENTRATION:
switch (chan->channel2) {
case IIO_MOD_CO2:
*val = be16_to_cpu(data->buffer.co2);
ret = IIO_VAL_INT;
break;
case IIO_MOD_VOC:
*val = be16_to_cpu(data->buffer.voc);
ret = IIO_VAL_INT;
break;
default:
ret = -EINVAL;
}
break;
default:
ret = -EINVAL;
}
mutex_unlock(&data->lock);
iio_device_release_direct_mode(indio_dev);
return ret;
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_VOLTAGE:
*val = 1;
*val2 = 612903;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CURRENT:
*val = 0;
*val2 = 1000;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CONCENTRATION:
switch (chan->channel2) {
case IIO_MOD_CO2:
*val = 0;
*val2 = 100;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_MOD_VOC:
*val = 0;
*val2 = 100;
return IIO_VAL_INT_PLUS_NANO;
default:
return -EINVAL;
}
default:
return -EINVAL;
}
default:
return -EINVAL;
}
}
static const struct iio_info ccs811_info = {
.read_raw = ccs811_read_raw,
};
static int ccs811_set_trigger_state(struct iio_trigger *trig,
bool state)
{
struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
struct ccs811_data *data = iio_priv(indio_dev);
int ret;
ret = i2c_smbus_read_byte_data(data->client, CCS811_MEAS_MODE);
if (ret < 0)
return ret;
if (state)
ret |= CCS811_MEAS_MODE_INTERRUPT;
else
ret &= ~CCS811_MEAS_MODE_INTERRUPT;
data->drdy_trig_on = state;
return i2c_smbus_write_byte_data(data->client, CCS811_MEAS_MODE, ret);
}
static const struct iio_trigger_ops ccs811_trigger_ops = {
.set_trigger_state = ccs811_set_trigger_state,
};
static irqreturn_t ccs811_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ccs811_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
s16 buf[8]; /* s16 eCO2 + s16 TVOC + padding + 8 byte timestamp */
int ret;
ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA, 4,
(u8 *)&buf);
if (ret != 4) {
dev_err(&client->dev, "cannot read sensor data\n");
goto err;
}
iio_push_to_buffers_with_timestamp(indio_dev, buf,
iio_get_time_ns(indio_dev));
err:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private)
{
struct iio_dev *indio_dev = private;
struct ccs811_data *data = iio_priv(indio_dev);
if (data->drdy_trig_on)
iio_trigger_poll(data->drdy_trig);
return IRQ_HANDLED;
}
static int ccs811_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct ccs811_data *data;
int ret;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE
| I2C_FUNC_SMBUS_BYTE_DATA
| I2C_FUNC_SMBUS_READ_I2C_BLOCK))
return -EOPNOTSUPP;
/* Check hardware id (should be 0x81 for this family of devices) */
ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
if (ret < 0)
return ret;
if (ret != CCS811_HW_ID_VALUE) {
dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
return -ENODEV;
}
ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
if (ret < 0)
return ret;
if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
dev_err(&client->dev, "no CCS811 sensor\n");
return -ENODEV;
}
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
ret = ccs811_setup(client);
if (ret < 0)
return ret;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
mutex_init(&data->lock);
indio_dev->dev.parent = &client->dev;
indio_dev->name = id->name;
indio_dev->info = &ccs811_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ccs811_channels;
indio_dev->num_channels = ARRAY_SIZE(ccs811_channels);
if (client->irq > 0) {
ret = devm_request_threaded_irq(&client->dev, client->irq,
ccs811_data_rdy_trigger_poll,
NULL,
IRQF_TRIGGER_FALLING |
IRQF_ONESHOT,
"ccs811_irq", indio_dev);
if (ret) {
dev_err(&client->dev, "irq request error %d\n", -ret);
goto err_poweroff;
}
data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
"%s-dev%d",
indio_dev->name,
indio_dev->id);
if (!data->drdy_trig) {
ret = -ENOMEM;
goto err_poweroff;
}
data->drdy_trig->dev.parent = &client->dev;
data->drdy_trig->ops = &ccs811_trigger_ops;
iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
indio_dev->trig = data->drdy_trig;
iio_trigger_get(indio_dev->trig);
ret = iio_trigger_register(data->drdy_trig);
if (ret)
goto err_poweroff;
}
ret = iio_triggered_buffer_setup(indio_dev, NULL,
ccs811_trigger_handler, NULL);
if (ret < 0) {
dev_err(&client->dev, "triggered buffer setup failed\n");
goto err_trigger_unregister;
}
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(&client->dev, "unable to register iio device\n");
goto err_buffer_cleanup;
}
return 0;
err_buffer_cleanup:
iio_triggered_buffer_cleanup(indio_dev);
err_trigger_unregister:
if (data->drdy_trig)
iio_trigger_unregister(data->drdy_trig);
err_poweroff:
i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE, CCS811_MODE_IDLE);
return ret;
}
static int ccs811_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct ccs811_data *data = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
if (data->drdy_trig)
iio_trigger_unregister(data->drdy_trig);
return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
CCS811_MODE_IDLE);
}
static const struct i2c_device_id ccs811_id[] = {
{"ccs811", 0},
{ }
};
MODULE_DEVICE_TABLE(i2c, ccs811_id);
static struct i2c_driver ccs811_driver = {
.driver = {
.name = "ccs811",
},
.probe = ccs811_probe,
.remove = ccs811_remove,
.id_table = ccs811_id,
};
module_i2c_driver(ccs811_driver);
MODULE_AUTHOR("Narcisa Vasile <narcisaanamaria12@gmail.com>");
MODULE_DESCRIPTION("CCS811 volatile organic compounds sensor");
MODULE_LICENSE("GPL v2");
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